XVI International Botanical Congess

Biodiversity within the northern ecosystems is lower than in tropical ecosystems in the number of species. Many species have wide distributions, and genetic variation is an important component of the total biological diversity. Genetic diversity is dynamic, and a suitable conservation goal is to preserve processes that generate, distribute and maintain the variation. The processes are described in the light of examples from boreal and temperate forests. Migration and genetic drift have equal consequences for all neutral loci, but natural selection produces different results, depending on the adaptive role. Indicators for maintenance of the genetic processes overlap partly with the indicators that are used for assessing the ecological or demographic condition of the forest ecosystem. Demographically healthy populations are likely to be genetically sound.